The energy needs of society are constantly growing. Techniques to meet this growing energy demand are continually sought after. One area of focus has been in the area of solar power. Solar power technology can take various forms. For instance, various types of photovoltaic devices are known in the art (e.g., see U.S. Patent Document Nos. 2004/0261841, 2006/0180200, 2008/0308147; U.S. Pat. Nos. 6,784,361, 6,288,325, 6,613,603, and 6,123,824, the disclosures of which are each hereby incorporated by reference).
In certain instances, photovoltaic (PV) devices are installed as part of a solar farm, onto the roof of a residential building, or the like. These devices may sometimes also include a tracking system that operates to continually adjust the positioning of the device such that direct sunlight approaches the PV device from a direction that is perpendicular to the surface of the PV device. While this technique may improve the overall efficiency of PV systems, the additional cost and parts required for maintaining such a tracking system may increase costs in other ways.
One issue with solar power is that it may require a large land footprint. As land can be expensive and/or limited (e.g., in urban and suburban contexts), this can also raise the cost of solar powered systems and/or otherwise restrict their feasibility.
One way to address this land requirement is to install a PV system as part of an existing structure, such as a building or dwelling. Such an arrangement may be beneficial in that buildings can have large vertical footprints, especially skyscrapers and larger buildings, while having a relatively small land footprint. Further, the sides (and top) of these buildings may have significant exposure to direct or indirect sunlight.
One technique for making use of the vertical space occupied by these building is to install PV devices on or as a part of the building structure. Such PV systems are conventionally referred to as building-integrated photovoltaic (BIPV) systems or building-applied photovoltaic (BAPV) systems. Such systems can (but not always) replace or augment conventional building materials that are used as part of the building. For example, a shingle on a house or a window on an office building can sometimes be replaced with a device and achieve the same or similar functionality to a regular shingle or window, but also provide for collection of solar power from an associated PV device.
FIG. 7 shows a conventional BIPV device 700 that comprises a stack of semiconductor layers 712 or a semiconductor wafer that is laminated to a glass substrate 720 via a laminate layer 714. Such a system 700 may collect at least some direct sunlight 706 and/or at least some diffuse light 718. However, as BIPV systems typically do not track the sun (e.g., as with some solar power installations) because the walls and/or roofs cannot move, the energy conversion efficiency may depend on the relative position of the sun.
Thus, the typical flat and vertical installation BIPV system shown in FIG. 7 may have high light reflection 710 when the sun is located at a shallow angle to the surface of the glass substrate. The surface of the glass substrate 720 has a normal vector 708 that may represent an “optimum” angle from which reflection of solar energy is reduced. Thus, when energy is arriving at a shallow angle, the angle to the surface normal is increased. To complicate matters further, the time of day when the sun may provide the most energy is when it is also at the highest point in the sky (e.g., solar noon). During this high point, the angle of incidence to the plane of the glass of the BIPV system may be near or at its shallowest point. Thus, while this point may be when the energy hitting the surface of the glass substrate 720 is at its highest, the reflection percentage may also be at its highest. This can cause reduced operating efficiency of the installed BIPV system (e.g., because more light is reflected due to the low angle).
Accordingly, it will be appreciated that it would be desirable to provide new and improved techniques for developing, producing, manufacturing, PV systems for building adapted or building integrated systems.
In certain example embodiments, a BIPV/BAPV system increases the amount of light (energy) being “harvested” by reducing the amount of light reflected from the glass substrate that fronts the semiconductor layer of an exemplary BIPV/BAPV system.
In certain example embodiments, a patterned glass (e.g., patterned float glass) substrate is coupled with a semiconductor layer. This patterned glass element may be asymmetric in nature and provide reduced light reflection when the sun is at a high point (e.g., because a surface normal from a surface of the asymmetric pattern is closer to a vector that represents direct sunlight.
In certain example embodiments, a photovoltaic system may be used in a BIPV or BAPV assembly.
In certain example embodiments, there is provided a component adapted for use with a building integrated photovoltaic (BIPV) or a building adapted photovoltaic (BAPV) system. An asymmetric glass substrate includes first, second, and third surfaces when viewed in cross section, with the asymmetric glass substrate being substantially triangular shaped in cross section such that the third surface is longer than the first and second surfaces. The third surface is adapted to be laminated to a photovoltaic device. The first surface is configured to angle away from a vertical plane of a building at an angle of between 5 and 40 degrees. The first surface has a length that is greater than a length of the second surface.
According to certain example embodiments, there may be provided an array that includes a plurality of the components described in the preceding paragraph.
In certain example embodiments, there is provided a photovoltaic system adapted for integration into and/or connection onto a building. At least one photovoltaic module is adapted to be disposed along at least a portion of a side of the building. A glass substrate has a first major surface adjacent to the at least one photovoltaic module. The glass substrate is patterned opposite the first major surface so as to form a plurality of modules, each said module including first and second edge portions, with the first edge portion being angled away from the at least one photovoltaic module and with the second edge portion being angled towards the at least one photovoltaic module such that the first and second edge portions, together with the first major surface, are substantially triangularly shaped when viewed in cross section.
In certain example embodiments, a method of making an asymmetric component for a building integrated photovoltaic (BIPV) or a building adapted photovoltaic (BAPV) system is provided. At least a portion of a glass substrate is shaped into an asymmetric patterned shape that includes a first surface, a second surface, and a third surface. The third surface is adapted to be laminated to a photovoltaic device. The first surface is shaped such that an acute angle between a plane that is parallel to the first surface and a vertical plane of a building is formed, with the acute angle being between 5 and 40 degrees. The first surface has a length that is greater than a length of the second surface. The asymmetric patterned shape is substantially triangular when viewed in cross section.
In certain example embodiments, a method of making a photovoltaic system for a building is provided. A plurality of components may be made in accordance the method of the previous paragraph. At least one photovoltaic module is oriented against at least a portion of at least some of the third surfaces.
The features, aspects, advantages, and example embodiments described herein may be combined in any suitable combination or sub-combination to realize yet further embodiments.